Switch structure



'May 4, 1948. c. D. MULLIN 2,440,807

SWITCH STRUCTURE Filed Feb. 21, 1944 Patented May 4, 1948 SWITCH STRUCTURE ClaytonDavis Mullin, St. PaulgMinm, assignor to.

Telexv Products Company; St. Paul, Minn, a corporation of Minnesota Application February 21, 1944', Serial No. 523,197

(Cl; (l-153) 13 Claims.

This invention relatesto a switch, and" while the switch could have various applications and be used in many places, in ractice it has-been used as a switch in'a hearingaid. It is desirable to have a small compact switch which can be easily operated so as to bemovedto its off and on positions. It is also desirable to have a switch havin stops limitin the movement of its control member so that one turning it can feel its position. It is also desirable to have astructurev in which the operator can feel when the switch reaches its closed position.

It is an object ofthis invention therefore, to provide a simple, compact switch of the rotary type: having an operating means: preferably in the form of a rotatable handle and so constructed and arranged that the operator" can feel when the'switch is in closed position.

It is a further object oftheinvention to provide such a switch as above set forth in which stops are provided limiting the rotationof' the operating means or handle-so that the operator can tell that the switch is in o position-when one. of the stops are engaged.

It is still further anobject of the invention to provide a switch comprising a rotatable disk'having contact means thereon and projecting from its periphery, an armresiliently movable toward said diskand having a contact portionadapted to engage said contact means together witha, cam member for lifting said-arm andpermitting said contact means to engage said-contactportiom- Itisalso an object of the invention to-provide such a switch as set forth-in the preceding paragraph in which said disk is frictionally' rotated and in which said cam is rotated to lift'saidarm in moving said switch to both on and off positions.

It is more specifically-an object of theinvention to provide a switch comprising a casing preferably of cylindricalform, a handle-at one end of said casing, a shaft rotated by said handle, a cam secured to said shaft, a disk adjacent said cam and frictionally engagedsoasto-be rotated by saidhandle when unobstructed and an arm resiliently moved toward, said disk and cam-and adapted to be lifted by said cam topermit a contact portion ofv said disk' to engage and be dis-- engaged from the contact portion of said arm'.

These and other objects-and-advantagesof the invention will be fully setforth in the following description made in connection with the. accompanying drawings in which like reference characters refer to similarpartsthroughout-the several views and in which:

Fig. 1 is a view-in front elevation of the switch;

Fig. 2 is a top plan view;

Fig.- 3 is a view in rear elevation, being omitted;

Fig; 4 is a view in rear elevation, eingbroken away;

Fig. 5; is a view similar to Fig. 4 showing the parts in a diiferentposition;

Fig. 6 is a view similar to Fig. 4 showing the switch in' open position;

Fig. '7 is a view in rear elevation, some parts beingbroken away and others shown in vertical section;

Fig. 8 isa view similar to'Fig. '7, some parts being-omitted;

Fig. 9-is a view in front elevation of one of the elements;

Fig. 10 is a vertical section taken on line lt.lii of Fig. '7 as indicated by the arrows;

Fig. 11 is a vertical sectional taken on line I l|| of Fig. 8 as indicated by the arrows; and

Fig. 12 is a view in elevation of the-contact disk and-cam used.

Referring to the drawings a switch isshown comprising a casing 26 and while this might be variously formed, in the embodiment of the invention illustrated itis shown as of cylindrical form. Casing 28 hassecured thereto and projecting from substantially opposite sides thereof lugsZM-and 20bby means of which it may be secured to theframe of the instrument with which the switchis used. An operating handle some parts some parts 2| is providedfor the switch, and while this might.

bevariously formed, in the embodiment of the invention illustrated; it is shown as in the form of adisk or wheel having projecting flutes or ribs 2m adjacent its edge, the same being circumferentially spaced. A shaft 22- is securedin handle 2|- coaxially therewith and projects therefrom, the same having a fiat portion 22 on which is received a cam member .23 made of insulating material. Cam 231s provided with a slot 23a fitting portion 22a and saidcam also has a cam lu 23b projecting from its periphery. Handle 2! 3 jecting therefrom which seats in a notch 28d in the rear of said casing so that disk 25 is held from rotation. Disk 25 has secured to its rear side an annular member 26 made of high resistance material and a pair of small diverging contact tongues 28 project outwardly from one side of disk 25, the same being secured to members 25 and 26 by rivets 29 which pass through small metallic plates 30 engaging the rear of annular member 26. A disk-like member 32 is secured to the inner face of handle member 2| by a screw 33 and is split to be brought into tight engagement with shaft 22. A partly annular member 34 is secured to opposite sides ofmember 32 adjacent its outer edge, being attached thereto in any suitable manner as by solder 35, said member 35 being formed of a group of fine wires of conducting material. Member 3% projects inwardly from member 32, being formed with a substantial point 34a at its central part which resiliently engages member 26. A thin metallic washer 36 surrounds shaft portion 22a and is disposed between cam 23 and strip 24. Washer 38 is provided with rectangular slot fitting shaft portion 22a. A contact disk 38 of conducting material or metal is apertured to surround a forwardly projecting hub on cam member 23. Disk 38 has spaced lugs 38a and an apertured lug 3312 projecting from its periphery. The part between lugs or teeth 38a is of greater diameter than cam 23. A spring washer 39 overlies disk 38 and is in turn engaged by a washer 49 of insulating material. The outer portion or shaft 22 is threaded and received a nut 4| which holds washer 50 against spring washer 39. An arm 43 of resilient conducting material such as metal has an apertured lug 43a engaging the rear side of lug 2th and is secured to said lug by a headed screw 44 provided with a nut 45. Screw 44 may also serve to attach casing 2|] to the adjacent parts. Arm d3 isbent at its end to form a V-shaped portion 3% and this portion is in line laterally with cam 23 and disk 38. The member 32 is provided'with a short semi-annular flange 32a moving substantially in engagement with the inner wall of casing 28 and'said casing is provided with an inwardly projecting lug 200 with which the opposite sides or ends of flange 3211 respectively engage.

The switchis moved to.-on and oif positions by rotation of handle 2| which rotates relatively to casing 20. Rotation of handle 2| rotates shaft 22 and this in turn rotates cam 23. Disk 38 is also frictionally rotated when shaft 22 and cam 23 are rotated and said disk will thus move with cam 23 unless held from movement. The turning friction is exerted on disk 38 by spring washer 39; As handle 2| rotates plate 32 and conductor 34 rotate. Arm 43 forms one main contact of the switch and portion 43b is the contact portion. When portion 43b is seated between the projections or teeth 38a the switch is in closed position. The switch is shown in off position in Fig. 6. At this time disk 38 has been rotated in a counter clockwise direction as shown in said figure, until the projections 33a have moved to the left of portion 43b. The cam lug 23b has moved just to the left of portion 43b and at this time the end of flange 32a is engaging lug or projection 200 so that the handle 2| cannot be turned any farther in a counterclockwise direction. A stop is thus provided for the oif position of the switch and since handle 2| cannot be farther turned, disk 38 stops in the position shown in Fig. 6. To move the switch to "on pcsitien handle 2| will be rotated in a clockwise direction as shown in Figs. 3 to 6 and when this is done lug 23b moves or lifts portion 531) so that the leading projection 3811 can pass thereunder. Portion 43b is shown in this lifted position in Fig. 5. The leading tooth or projection 38a is just about to pass under portion 43b. When cam lug 23b passes portion 43b the latter moves down between projections 38a and the switch is then in closed position as shown in Figs. 3 and 4. Disk 38 is held from further rotation in a clockwise direction by engagement therewith of portion 43b. The handle 2| however, can be moved through almost a revolution and until the other end of flange 32a engages lug or projection 290 as shown in Fig. 8. This extra movement of the handle and cam 23 is provided for the operation of member 36%. The projections 28 form terminals of one auxiliary volume control circuit. Member 24 is provided to connect with shaft 22 and as described, member 24 has a lug 24b engaging lug 26a so that a connection of an auxiliary circuit can be made therewith. As handle 2| is'rotated the pointed portion 34a of conductor 34 moves along in engagement with high resistance member 26 and as handle 2| is moved in a clockwise direction as shown in Figs. 3 to 8, more resistance is cut into an auxiliary volume circuit. Conversely when handle 2| is again moved in a counterclockwise direction resistance is cut out of said volume circuit so that the volume of the hearing aid decreases until cam lug 23b again lifts portion 43b in its counterclockwise movement and the switch is moved'to o position. The volume is at a minimum just before the switch moves to 01f position. It will be noted that with the switch in 01f position portion 43b is held out of contact with disk 38 by engaging the periphery of cam 23 which is of slightly larger diameter than disk 38. The handle 2| therefore, and shaft 22 function not only to close and open the switch but also to control the volume of the hearing aid.

The switch is used to open and close the battery circuit in the hearing aid. The operator can feel the switch move to on position and can also feel the switch move to foif position as resilient arm 53 moves back after being raised by cam lug 23b. The operator can also alway know the position of the switch by turning handle 2| until the stops are engaged by movement in opposite directions. Since the handle is against one stop when the switch is in off position this could always be used as a starting point or locating point for telling the position of the switch. The operator will thus soon learn to know the position of the switch without observing any marks or in dications. d

From the above description it will be seen that I have provided a very compact, simple and ellicient switch and volume control means and one that is particularly adapted for use in a hearing aid. The switch is quite compact and in actual practice the diameter of casing 20 has been made less than of an inch. The structure is well designed to be connected to the frame of the hearing aid. As the V-shaped or pointed portion 43b slides over the teeth 3811 it has a scraping and cleaning action so that the contacts are kept bright and clean, assuring a good electrical connection. The action of the switch is quite positive and as stated, the operator can tell by the feel of the device what the position of the switch is. The device is easily and conveniently operated. The same has been amply demonstrated in actual practice, found to be very. successful and efiicient and is being commercially made.

rangement andproportionsof the parts, without departing from the-scope of applicants invention, which generally stated,-consists in a device capable of carrying-out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is: i l. A-switch having in combination, a movable contact member having acontact means projecting therefrom, a second contact member having a contact portion disposed so as 'to engage said contact means-and being urged toward' s'aid contact means and a member movable adjacentsaid first mentioned contact -mem'ber arranged "to -move said contact portion sothat said contact means may e moved into alignment with and be engaged by said contact portion.

2. A switchhaving in combination, a rotatable contact member having a periphery and a contact means projecting therefrom, a second contact member having a contact portion urged toward said periphery and means'movable adjacent said periphery to lift said contact portion and permit said contact means to move into alignment with and be engaged by said contact portion.

3. A switch having in combination, a'rotatable metallic disk having spaced projections on the periphery thereof forming a contact means, a movable arm having a portion resiliently moved toward said periphery and adapted to seat between and engage said projections when said switch is in closed position, a member movable adjacent said disk having a portion disposed so as to engage said first mentioned portion and move the same away from said disk so that said projections may be moved thereunder in the rotation of said disk to ali with and be engaged by said contact portion.

4. A switch having in combination, a metallic disk, means for frictionally rotating said disk, said disk having a contact means on its periphery, a resiliently mounted arm having a contact portion adapted to engage said contact means, a rotatable cam adjacent said disk having a portion adapted to lift said arm so that said contact portion may move into engagement with said contact means in the rotation of said cam and disk.

5. A switch having in combination, a rotatable metallic disk having a projecting contact means on its periphery, an arm resiliently moved toward said periphery and having a portion adapted to engage said contact means when the switch is in closed position, a rotatable cam adjacent said disk having a portion adapted to engage said portion of said arm and move the same so that said contact means on said disk may align with and be engaged by said contact portion of said arm in the rotation of said cam and disk, means for rotating said disk and a stop for limiting the rotation of said means and cam with said switch in off position and said contact portion and contact means out of alignment.

6. A switch having in combination, a shaft, a handle secured to said shaft for rotating the same, a cam secured to said shaft and rotatable therewith, a metallic disk disposed adjacent said cam having a contact means on its periphery, means on said shaft and frictionally engaging said disk so that said disk is frictionally rotated with said cam, an arm resiliently moved toward closed position, said cam having a portion adapted to engage said portion of said arm and lift the same so that said contact means can move into alignment with and be engaged by said contact portion.

7, 'A switch havingin combination, a casing constructedandarranged tobe attached to a frame, a disk-like'handle engaging and-rotatable at one end of said casing, a shaft carried by said handle, a cam secured to said shaft, a contact disk having a pair of spaced projections onits periphery, means engaging said disk for frictionally rotating the same when said cam is rotated, a resilient arm having a contact portion aligned with said cam anddisk, said cam having a projection adapted-to move said contact portion and permit one of said projections to pass the same so that said contact portion may engage saiddisk between said projections in therotation of said cam inone direction, said cam pr-ojection'being adapted to raise said contact portion to permitsaid projection to pass said contact portion and. disengage said disk in able metallic diskhaving a projecting contact 'means on its periphery, an arm resiliently moved toward said periphery and having a portion adapted to engage said contact means when the switch is in closed position, a handle, a rotatable cam moved with said handle adjacent said disk having .a portion adapted to engage said contact portion and move the same so that said contact means on said disk may align with and :be engaged by said contact portion of said arm in the rotation of said cam and disk in one direction, said disk being frictionally movable with said cam and stops for limiting the rotation of said cam and handle in both directions, said cam moving said contact portion to permit said contact means to pass out of alignment with said contact means as said cam and disk are rotated in the opposite direction.

9. A switch and control structure havin in combination, a rotatable contact member having a projecting contact means, a second contact member having a contact portion urged toward said first mentioned contact member, a member rotatable adjacent said first mentioned contact member to move said contact portion to permit said contact means to align with and to be engaged by said contact. portion, means for rotating said last mentioned member and said first mentioned contact member, a stop engaged by said means when rotated in one direction with said contact means and contact portion out of alignment so that said switch is in open position and a stop engageable by said means when rotated a major portion of a revolution in the opposite direction after said contact means and contact portion have been engaged with said switch in closed position.

10. A switch and control structure having in combination, a contact disk having a projecting contact means thereon, a contact member having a contact portion urged toward said disk, a cam movable adjacent said disk, said disk being frictionally rotated with said cam, a handle for rotating said cam and disk, said cam lifting said contact portion to permit said contact means to move out of alignment with said contact portion in the rotation of said cam and disk in one direction, a

stop for limiting the movement of said handle after said contact means has moved out of alignment with said contact portion in the rotation of said handle in one direction and with said switch in open position and a stop limiting the movement of said handle in the opposite direction after the same has been moved through a major portion of a revolution after said contact means and contact portion have become engaged with said switch in on position.

11. A switch and control structure having in combination, a revoluble contact member having a contact means thereon, a second contact memher having a contact portion, a handle for rotating said revoluble contactmember in one direction to position said contact means in spaced relation with said contact portion to place said switch in open position, a stop for limiting movement of said handle with said switch in open position, said handle being rotatabl in the other direction to bring said contact means and contact portion into engagement to place said switch in closed position, said handle being further rotatable in said other direction for a major portion of a revolution, and a stop limitin movement of said handle after said further rotation.

12. A switch and control structure having in combination, a movable member having a projecting contact means, an arm resiliently moved toward said member and having a contact portion adapted to engage said contact means when said switch is in closed position, a movable cam adjacent said member having a Portion arranged to engage said contact portion and move the same so that said contact means may align with and be engaged by said contact portion of said arm in the movement of said member and arm, and means for moving said cam.

13. A switch having in combination,- a metallic disk, means for frictionally rotating said disk, said disk having a projecting contact means thereon, a resiliently mounted arm having a contact portion urged toward and adapted to engage said contact means, a rotatable cam adjacent said disk having a portion adapted to lift said arm so that said contact portion thereof may be moved into engagement with said contact means in the rotation of said cam and disk.

CLAYTON DAVIS MULLIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES I PATENTS Number Name Date 2,186,154 Stoekle Jan. 9, 1940 2,231,541 Lodge Feb. 11, 1941 2,285,577 Gary June 9, 1942 

